Roller skates and skate boards are common roller-type exercising devices and somewhat less common are skis having rollers mounted thereon for summer use. In most all instances the wheels are mounted on straight through axles that extend transversely across the platform or boot for the rider or user, as the case may be. In roller skates the axle is fixed to the sole of the boot and the wheels are in a fixed location at all times with respect to the boot sole. On skate boards the wheel axles are transverse to the board but are pivotally mounted whereby the board can be tilted to a limited extent with respect to one of the two sets of wheels.
In Canadian Pat. No. 197,629, issued Mar. 2, 1920 to Maurice Block there is disclosed a roller skate type device consisting of a plate attachable to the sole of a boot and wherein the wheels are mounted on a crank-type axle. The opposite ends of the crank project laterally respectively from opposite sides of the boot, one being at the front and the other near the rear. The central portion of the crank extends longitudinally of the boot or plate and is pivotally attached thereto so that the boot can be tilted from one side to the other. This tilting is used to steer the front wheel by way of a suitable linkage mechanism actuated by the tilting. The wheels, however, remain always in an upright position.